Clutches are employed to assist in the engagement and disengagement of drive trains and other power driven equipment. The benefit of the use of a clutch can be that the power train can be disconnected without stopping the power source, such as an engine, motor or the like. In other situations, a clutch can be used to disconnect the power source from the load so that the load can be moved without affecting the power source.
Winches and hoists include examples of the use of clutches to connect and disconnect the load from the power source. Vehicle winches are generally driven by a reversible DC motor to rotate a cable drum one direction or an opposite direction to wind and unwind the cable from the drum. When it is desired to play out the cable from the drum, for example, to pull the cable therefrom to connect the end of the cable to an object, the clutch is engaged to allow the drum to spool freely and allow the cable to be pulled therefrom without also turning the DC motor. Once the cable is played out a desired length and connected to the load, the clutch is disengaged to thereby allow the DC motor to turn the drum and wind the cable thereon and pull the load toward the winch. There are many types of winch clutches that are manually operable to engage and disengage the cable drum from the driving motor. Examples of manual and other types of clutches are described in U.S. Pat. Nos. 4,396,102; 4,379,502; 4,192,409; 4,187,936; 4,084,793; and 3,986,588.
While the mechanical or manual clutches function well to engage and disengage loads from the power source, such devices require the operator to be present and in the immediate vicinity of the winch. There are instances where it is desirable that the operator to be at a location remote from the winch, but yet able to control the winch. U.S. Pat. No. 5,522,582 discloses a remote controlled winch that is equipped with a long electrical umbilical cord with a control so that the operator can control the winch without having to manually operate push switches located on the winch itself. U.S. Pat. No. 6,995,682 discloses a wireless remote control for a winch, where a hand-held unit electrically controls the on-off status and the forward/reverse mode of operation of the winch in a wireless manner.
It is a common practice to incorporate a clutch in a winch of the type employing planetary gear reduction apparatus. It is well known that the use of planetary gear reduction apparatus involves a ring gear and sun gears to achieve the gear reduction function. The planetary gear reduction apparatus can include one or more stages to achieve the degree of reduction in the rpm of the cable drum 36 with respect to the driving source. In many winches, including the types without clutches incorporated in the planetary gear assembly, the ring gear of the planetary gear reduction assembly is attached to the case or housing of the winch to prevent rotational movement. In winches of the types incorporating clutches with the planetary gear assemblies, the ring gear is maintained stationary when the clutch is disengaged so that normal gear reduction functions can be carried out. However, when it is desired to engage the clutch and disconnect the power source from the cable drum, the ring gear is allowed to rotate with the sun gears and other associated gears, thereby effectively disconnecting the power source from the cable drum.
The clutch/planetary gear assembly is generally operated using a rotatable ring gear with a notch in the periphery thereof, and a pin that can be moved in and out of the notch to allow rotation or prevent rotation of the ring gear. The pin can be moved either manually using a lever, or electrically using a solenoid where the plunger functions as the pin. Such a winch clutch is described in U.S. Pat. No. 5,842,684. The solenoid is of the type that must be continuously operated during clutch engagement. When the winch is battery powered, as are many vehicle winches, the continuous use of current from the battery of the vehicle can be a concern.
From the foregoing, it can be seen that a need exists for a clutch that can be remote controlled using wireless means, and that does not require electrical energy during periods of engagement. Another need exists for a winch control where, once the clutch is engaged, it can be automatically disengaged when the power source is operated to control the winding or unwinding of the cable with respect to the drum.